IMBIV   05474
INSTITUTO MULTIDISCIPLINARIO DE BIOLOGIA VEGETAL
Unidad Ejecutora - UE
artículos
Título:
Cryptic genetic diversity and geographic distribution of polyploidy in Solanum elaeagnifolium Cav.
Autor/es:
BERNARDELLO G.; SCALDAFERRO MARISEL; CHIARINI F.; ACOSTA M. C.
Revista:
AUSTRALIAN JOURNAL OF BOTANY
Editorial:
CSIRO PUBLISHING
Referencias:
Lugar: Collingwood; Año: 2018 vol. 66 p. 531 - 540
ISSN:
0067-1924
Resumen:
Background and Aims: Polyploidy is a frequent phenomenon that behaves as a source of genetic variability, conferring adaptive advantages. Solanum elaeagnifolium or "silverleaf nightshade" (SLN), a global invasive weed with an alleged origin in North America, presents diploid and polyploid populations in Argentina. We aimed to determine the native range of SLN, the origin and distribution of diploid and polyploid lineages, and the relationship of poliploidy with the invasion of new habitats, using a phylogeographic approach. ●Methods: We studied 26 natural populations. Ploidy level was determined using classical cytogenetic techniques. Total DNA was extracted and two non-coding regions of the chloroplast were amplified using primers trnL-trnF and rpl32F-trnL. Relationships among haplotypes were examined by a median-joining network and groups of populations were identified using a spatial analysis of molecular variance. Diversity indices were calculated, together with a ´mismatch distribution´ analysis to assess population stasis. Expansion models were evaluated using parametric bootstrapping plus neutrality tests. Changes in effective population sizes were assessed through Bayesian skyline plots. Divergence times were estimated using BEAST. ●Key results: We found 21 haplotypes, which are structured into three lineages: one with diploids in North America and invaded areas, and the other two in South America, which developed independent events of polyploidization. The separation of the lineages took place during the Pliocene, with recent divergences and population expansion in the Early Pleistocene. ●Conclusions: The South American populations of SLN did not originate from a recent colonization, but are established ancient lineages. The existence of three lineages can be attributed to the development of the Andean Cordillera, and the emergence of the Isthmus of Panama. Diversification within each lineage may be related to the recent cyclical advance and retreat of glaciers throughout the Pleistocene, what might have caused haplotype diversity, together with recurrent polyploidy.